More Information Retrieval Books
The Turn - Integration of Information Seeking and Retrieval in Context. P. Ingwersen, K. Järvelin. Springer, 2005. Attempts to create a unifying framework for cognitive IR research.
Charting a New Course - Natural Language Processing and Information Retrieval.: Essays in Honour of Karen Sparck Jones. J.I. Tait (ed). Kluwer, 2005. With contributions by D. Harman, C.J. van Rijsbergen, S. Robertson, Y. Wilks, P. Willet and others.
Understanding Search Engines: Mathematical Modeling and Text Retrieval. M.W. Berry, M. Browne. SIAM, 1999. Strong emphasis on latent semantic indexing.
Information Retrieval: Data Structures & Algorithms. W.B. Frakes and R. Baeza-Yates. Prentice-Hall, 1992. Mostly superseded by Baeza-Yates et al. 1999.
Information Storage and Retrieval. R.R. Korfhage. Wiley, 1997. Older textbook. Better coverage of library science issues.
Introduction to Modern Information Retrieval. G. Salton, M.J. McGill. McGraw-Hill, 1983. A classic. Difficult to find.